The present invention relates to the field of monopolar electrosurgery, and in particular to a monopolar electrosurgical return electrode.
Monopolar electrosurgical cutting and/or coagulation systems provide electrical current from an electrosurgical unit (ESU) to the active electrode, from where it is flows through the tissue to be cut and/or coagulated. While the supplied electrical current subsequently disperses through the patient body, it is ultimately collected within the return electrode to be returned to the ESU.
In this cycle flow, the current density at the interface between active electrode and tissue is moderate to high to perform the desired cutting and/or coagulation action, whereas the current density through the patient's body, as well as at the return electrode are low to prevent electrical burns. Even though the total current though the active electrode is the same as at the return electrode, the vast difference in current densities is due to largely different areas of the active electrode and the return electrode. The significant difference in current densities can change when either the return electrode is not connected properly to the patient, or when one or more sections of the return electrode accidentally separate from the patient's body. As such, unregulated or unchecked current density at the return electrode can cause unwanted thermal affects. It has also been found that a current density in excess 5 of 100 milliamperes per square centimeter would heat the body tissue beyond the threshold of necrosis.